The invention relates to a matrix display device comprising a receiving circuit for receiving successive frames, each frame comprising a set of original line luminance values D1, . . . DM of pixels d11, . . . d1N, . . . dM1 . . . dMN, the matrix display device further comprising a display panel comprising a set of display lines r1 . . . rM, and a driver circuit for supplying line luminance values to said display lines.
The invention also relates to a method of displaying successive frames, each frame comprising a set of original line luminance values D1, . . . DM of pixels d11, . . . d1N, . . . dM1 . . . dMN, on a display panel comprising a set of display lines r1,r2 . . . rN, extending in a first direction and a set of data lines intersecting the set of display lines, each intersection defining a pixel.
The invention is applicable, inter alia, in plasma display panels (PDPs), plasma-addressed liquid crystal panels (PALCs), liquid crystal displays (LCDs), which may be used for personal computers, television sets, etc.
As shown in FIG. 1, a matrix display panel comprises a first set of data lines (rows) r1 . . . rM extending in a first direction, usually called the row direction, and a second set of data lines (columns) c1 . . . cN extending in a second direction, usually called the column direction, intersecting the first set of data lines, each intersection defining a pixel (dot) d11 . . . dNM.
The matrix display furthermore comprises a receiving circuit 2 for receiving an information signal D comprising information on the luminance of lines to be displayed and means for addressing the first set of data lines (rows r1, . . . rM) in dependence on the information signal.
Such a display panel may display a frame by addressing the first set of data lines (rows) line by line, each line (row) successively receiving the appropriate data to be displayed.
In order to reduce the time necessary for displaying a frame, the double line addressing method may be applied. In this method, two neighboring lines of the first set of data lines (rows) are simultaneously addressed, receiving the same data. When two successive frames are considered, the pairs of lines in the second frame are shifted one line compared to the first frame.
This so-called double line (or, in general, multiple line) addressing method effectively allows speed-up of the display of a frame, because each frame requires less data, but at the expense of a loss of quality with respect to the original signal because each pair of lines receives the same data, which induces a loss of resolution and/or of sharpness due to the duplication of the lines.
Due to the ability of the human eye to merge signals which are displayed quickly after each other, when the double line addressing system is applied, the viewer cannot see the odd and even frames separately due to the quick frame change. But he can see the average value of these two frames. The average brightness of the image displayed may not correspond to that of the original image, thus resulting in a loss of resolution and/or sharpness.
It is an object of the invention to provide a method of addressing a matrix display panel with double line addressing where loss of resolution and/or sharpness with respect to the image obtained by single line addressing is reduced, and preferably minimized.
To this end, a first aspect of the invention provides a matrix display device as claimed in claim 1. A second aspect of the invention provides a method as claimed in claim 7. Advantageous embodiments are defined in the dependent claims.
In a display device in accordance with the invention, the average brightness is close to the brightness of the original image, as will be explained below.
According to the invention, a device using double line addressing comprises a computing unit for computing new line luminance values C0, . . . CM of pixels c11, . . . c1N, . . . cM1 . . . cMN as follows:
a first line luminance value C0 is initialized, for every other one of the line luminance values Cn, the line luminance value Cn is equal to twice the original line luminance value Dn for the nth line minus the line luminance value for the previous line Cnxe2x88x921 (Cn=2Dnxe2x88x92Cnxe2x88x921),
the driver circuit comprises means for supplying the line luminance values C0, . . . CM to said display lines r1 . . . rM in two successive subframes,
odd line luminance values C1, C3, . . . C2n+1, . . . being supplied to pairs of adjacent display lines (r1,r2), (r3,r4), . . . (r2n+1,r2n+2), . . . respectively, during one of said two successive subframes,
the line luminance value C0 and even line luminance values C2, C4, . . . C2n, . . . being supplied to the first display line r1 and to pairs of adjacent display lines (r2,r3), (r4,r5), . . . (r2n,r2n+1), . . . respectively, during the other of said two successive subframes.
Further improvements are described below and are the subject of the dependent claims.
These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiment(s) described hereinafter with reference to the accompanying drawings.